Dissolution Improvement of Poorly Water Soluble Drug Valsartan and Improving Flow Properties of Solid Dispersion

The aim of the present investigation is to improve the dissolution of poorly water soluble drug valsartan by preparing solid dispersions and also to evaluate the effect of different inert carriers on flow properties of solid dispersion. Valsartan is a poorly soluble drug useful in the treatment of hypertension. Absorption window of valsartan is stomach and upper part of small intestine. One possible way to improve dissolution rate is solid dispersions of the drug. The solid dispersions were prepared by solvent evaporation method using HPMC E5 LV as water soluble carrier, as use of HPMC low viscosity polymers for solid dispersion preparations were reported in literature. But film formation took place during solid dispersion formulation and was creating difficulty in releasing the drug from formulation; and those solid dispersions, were not free flowing. Thus such preparations are not useful from the formulation development point of view. So to improve the flow properties some inert material were tried like microcrystalline cellulose (MCC) and lactose. The solid dispersions were evaluated for drug content, solubility and dissolution studies. In vitro drug release of solid dispersions was studied by USP type II paddle dissolution apparatus. For the solid dispersion the solubility and dissolution of the drug increased with the increase in the carrier concentration. Probable mechanisms of improved solubility and dissolution were characterized by Differential Scanning Calorimetry (DSC), Powder X-ray Diffractometry (Powder XRD) and Scanning Electron Microscopy (SEM) of drug, physical mixture and solid dispersions. This study revealed that solid dispersions technique is promising and useful for valsartan to improve its solubility and dissolution and incorporation of inert carriers improved the flow property of solid dispersion.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Production and characterization of an organic solvent activated protease from haloalkaliphilic bacterium Halobiforma sp. strain BNMIITR

An unusual haloalkaliphilic bacterium known as Halobiforma sp. strain BNMIITR, which was noticed to produce an extracellular alkaline protease, was found in a soil sample from Northern India's Sambhar Lake. On the generation of protease, the effects of dietary elements including nitrogen and carbon sources, amino acids, and growth conditions like temperature and pH were investigated. When low-cost agricultural by-products were employed as nitrogen sources, the manufacturing of enzymes was significantly boosted. In the present study, protease production was enhanced by 2.94 fold and 2.17 fold. By solvent precipitation and Hydrophobic interaction chromatography (HIC) on Phenyl Sepharose 6 Fast Flow matrix, the enzyme was purified 31.67 fold. It was determined that the apparent molecular mass was 21 kDa. The pH range where the enzyme was most stable was 6.0–12.0, with a temperature of 50 °C as optimum. When there was alkaline earth metals and heavy metals, protease was discovered to be active. It was evident that the enzyme was a serine type of protease because it was active in the presence of a variety of surfactants, oxidizing and reducing chemicals, and phenylmethylsulfonyl fluoride (PMSF) completely inhibited activity. Enzyme exhibited a wide range of substrate specificity. Amazingly, enzyme remained stable both in polar and nonpolar solvents. The most interesting aspect of this enzyme is enhanced activity in polar solvents like dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). It was discovered that the protease was stable and compatible with a number of widely available detergents

Design, evaluation and statistical optimisation of a controlled release multiparticulate Acyclovir delivery system

El presente trabajo tiene por objeto el diseño y la evaluación de una forma de liberación controlada de Acyclovir utilizando etilcelulosa como polímero formador de la matriz y empleando la técnica de evaporación del solvente para la microencapsulación. El producto fue caracterizado por parámetros fisicoquímicos tales como el rendimiento (51%-86%), la eficiencia de retención de la droga (88% - 96%), el tamaño de partícula (principalmente tamiz de malla 30 ASTM), la topografía superficial, la compatibilidad droga-excipiente y la liberación in vitro (11% - 81% después de 8 h). El perfil de liberación controlada fue optimizado utilizando una mezcla de látex sencilla diseñada para lograr la combinación más adecuada de las micropartículas (proporción de partículas de relación droga-polímero 1:1 a 1:2 = 68%:32% de peso), que es el más apropiado para el perfil de liberación. El error entre el blanco perseguido (% de liberación a las 2 h, 6 h y 8 h de 40, 60 y 75, respectivamente) y la combinación óptima de las micropartículas fue menor que el 10%. El estudio demuestra la utilidad y ventajas del diseño experimental en la investigación de la liberación controlada de drogas.This work aims at designing and evaluating a multiparticulate controlled release dosage form of Acyclovir using Ethyl Cellulose as the matrix-forming polymer employing the solvent evaporation technique of microencapsulation. The product was characterized by physicochemical parameters such as yield (51%-86%), drug entrapment efficiency (88% - 96%), particle size (mainly #30 mesh ASTM), surface topography, drug-excipient compatibility and in vitro release (11% - 81% after 8 h). The controlled release profile was optimized using a simplex lattice mixture design for achieving the correct blend of microparticles (proportion of particles of drug-polymer ratio 1:1 to 1:2 = 68%: 32% by weight) that closely matches the target release profile. The error between the target (% release at 2nd , 6th and 8th h of 40, 60 and 75 respectively) and optimum blend of the microparticles was less than 10%. The study illustrates the utility and advantage of designed experimentation in controlled drug delivery research.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Design, evaluation and statistical optimisation of a controlled release multiparticulate Acyclovir delivery system

El presente trabajo tiene por objeto el diseño y la evaluación de una forma de liberación controlada de Acyclovir utilizando etilcelulosa como polímero formador de la matriz y empleando la técnica de evaporación del solvente para la microencapsulación. El producto fue caracterizado por parámetros fisicoquímicos tales como el rendimiento (51%-86%), la eficiencia de retención de la droga (88% - 96%), el tamaño de partícula (principalmente tamiz de malla 30 ASTM), la topografía superficial, la compatibilidad droga-excipiente y la liberación in vitro (11% - 81% después de 8 h). El perfil de liberación controlada fue optimizado utilizando una mezcla de látex sencilla diseñada para lograr la combinación más adecuada de las micropartículas (proporción de partículas de relación droga-polímero 1:1 a 1:2 = 68%:32% de peso), que es el más apropiado para el perfil de liberación. El error entre el blanco perseguido (% de liberación a las 2 h, 6 h y 8 h de 40, 60 y 75, respectivamente) y la combinación óptima de las micropartículas fue menor que el 10%. El estudio demuestra la utilidad y ventajas del diseño experimental en la investigación de la liberación controlada de drogas.This work aims at designing and evaluating a multiparticulate controlled release dosage form of Acyclovir using Ethyl Cellulose as the matrix-forming polymer employing the solvent evaporation technique of microencapsulation. The product was characterized by physicochemical parameters such as yield (51%-86%), drug entrapment efficiency (88% - 96%), particle size (mainly #30 mesh ASTM), surface topography, drug-excipient compatibility and in vitro release (11% - 81% after 8 h). The controlled release profile was optimized using a simplex lattice mixture design for achieving the correct blend of microparticles (proportion of particles of drug-polymer ratio 1:1 to 1:2 = 68%: 32% by weight) that closely matches the target release profile. The error between the target (% release at 2nd , 6th and 8th h of 40, 60 and 75 respectively) and optimum blend of the microparticles was less than 10%. The study illustrates the utility and advantage of designed experimentation in controlled drug delivery research.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Preparation, characterization and in-vitro evaluation of sunflower oil-Tween 80-Glycerol-based microemulsion formulation of a BCS class-II Drug

The aim of the present study was to prepare, characterize and in-vitro evaluation of a Winsor-IV type microemulsion based drug delivery system incorporating celecoxib as BCS class-II model drug. Attempts were made to prepare cost effective O/W microemulsion using Tween 80, Glycerol, sunflower oil and water. The existence of microemulsion zone was investigated using phase diagrams. The systems were characterized by polarized light microscopy, viscosity, refractive index, droplet size of dispersed phase by dynamic light scattering technique, thermal and centrifugal stability and the drug release profile. The obtained microemulsion was found optically isotropic with non-Newtonian behavior. The average droplet size was 100-300 nm. Microemulsions showed reversibility of transparency at ambient temperature after storage at 5 °C. The solubility enhancement of formulated products was apparent from higher release rate from microemulsion as compared to commercial product. The drug release profile was demonstrated to be promising for oral delivery of celecoxib.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Multiunit Floating Drug Delivery System of Rosiglitazone Maleate: Development, Characterization, Statistical Optimization of Drug Release and In Vivo Evaluation

A multiunit floating drug delivery system of rosiglitazone maleate has been developed by encapsulating the drug into Eudragit® RS100 through nonaqueous emulsification/solvent evaporation method. The in vitro performances of microspheres were evaluated by yield (%), particle size analysis, drug entrapment efficiency, in vitro floating behavior, surface topography, drug–polymer compatibility, crystallinity of the drug in the microspheres, and drug release studies. In vitro release was optimized by a {3, 3} simplex lattice mixture design to achieve predetermined target release. The in vivo performance of the optimized formulation was evaluated in streptozotocin-induced diabetic rats. The results showed that floating microspheres could be successfully prepared with good yields (69–75%), high entrapment (78-97%), narrow size distribution, and desired target release with the help of statistical design of experiments from very small number of formulations. In vivo evaluation in albino rats suggested that floating microspheres of rosiglitazone could be a promising approach for better glycemic control

New vegetation type map of India prepared using satellite remote sensing: Comparison with global vegetation maps and utilities

International audienceA seamless vegetation type map of India (scale 1: 50,000) prepared using medium-resolution IRS LISS-III images is presented. The map was created using an on-screen visual interpretation technique and has an accuracy of 90%, as assessed using 15,565 ground control points. India has hitherto been using potential vegetation/forest type map prepared by Champion and Seth in 1968. We characterized and mapped further the vegetation type distribution in the country in terms of occurrence and distribution, area occupancy, percentage of protected area (PA) covered by each vegetation type, range of elevation, mean annual temperature and precipitation over the past 100 years. A remote sensing-amenable hierarchical classification scheme that accommodates natural and semi-natural systems was conceptualized, and the natural vegetation was classified into forests, scrub/shrub lands and grasslands on the basis of extent of vegetation cover. We discuss the distribution and potential utility of the vegetation type map in a broad range of ecological, climatic and conservation applications from global, national and local perspectives. We used 15,565 ground control points to assess the accuracy of products available globally (i.e., GlobCover, Holdridge’s life zone map and potential natural vegetation (PNV) maps). Hence we recommend that the map prepared herein be used widely. This vegetation type map is the most comprehensive one developed for India so far. It was prepared using 23.5 m seasonal satellite remote sensing data, field samples and information relating to the biogeography, climate and soil. The digital map is now available through a web portal (http://bis.iirs.gov.in)